User Documentation

Program development
System manual
2696790000/02/04.2020
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7 Program development
The control operates based on the following principle: "Read inputs, pro-
cessing, right outputs". u-control carries out the following tasks during the
processing of each task defined with u-create studio:
● Read inputs: At the beginning of the cycle, the current statuses of the in-
puts are read and written into the process map of the inputs.
● Processing: The application program is executed. The set status of the
outputs is copied into the process map.
● Write outputs: At the end of the cycle, the set statuses of the outputs
saved in the process map are transmitted to the physical outputs.
Furthermore it is possible to create several applications in parallel or nested
and to start them on the control. A variable exchange between the applica-
tions is possible. For each application a symbol configuration can be cre-
ated.
Details about the programming can be found in the online help of u-create
studio.
7.1 Task priorities
IEC process priorities for a task can be assigned during programming. By
default priority 10 is configured for a task.
The following tables describe the assignment of the IEC task to the mapped
linux system task.
Reserved realtime tasks
Priority linux Description
99 - 82 Tasks of this priority are reserved for system
High prior real time tasks (default priority 10)
Priority linux Priority IEC
78 1
75 2
72 3
69 4
66 5
63 6
Low prior real time tasks
This tasks can be replaced at high workload and run in the linux scheduler
"SCHED_FIFO".
Priority linux Priority IEC
60 7